The characteristics of a Jack Kirby illustration are easily distinguished: extravagantly costumed heroes and nefarious villains locked in titanic struggles; foreshortened fists, feet and muscles that seem to pop off the page; intricately detailed settings meant to conjure the ancient past or suggest the distant future.

His style made Mr. Kirby a sought-after talent at DC Comics, now a piece of the Time Warner empire, and at Marvel Comics, a recent acquisition of the Walt Disney Company. At Marvel in particular he played a crucial role in creating superheroes like the Fantastic Four, the Hulk and the X-Men — work that is now at the center of a property dispute between the heirs of Mr. Kirby, who died in 1994, and Marvel and Disney.

Those same signature design elements are also vividly on display in hundreds of illustrations for never-produced cartoon shows and toy lines that Mr. Kirby created in the 1980s for the animation studio Ruby-Spears Productions — work that thus far does not belong to any of the media conglomerates and that has been seen by few people.

Now, a partnership between that studio’s founders, Joe Ruby and Ken Spears, and Sid and Marty Krofft, the longtime children’s entertainment producers (“H. R. Pufnstuf,” “Land of the Lost”), is planning to revive these unseen Kirby characters in as many forms as possible. It’s a proposition that faces challenges as the studios scour the landscape for the next comic book or cartoon character they can transform into a franchise, but also one that has piqued the interest of some powerful Hollywood players.

“I love comic books, but this is a treasure,” said Ariel Z. Emanuel, the co-chief executive of the William Morris Endeavor Entertainment agency, who is representing these Kirby works for Ruby-Spears and the Kroffts. “It’s like a boat sank at the bottom of the ocean, and all of a sudden you’ve uncovered it.”

Mr. Kirby started working for California’s animation studios in the late 1970s after becoming disillusioned with comic-book companies in New York that he said he felt did not give him fair payment or credit for his creations. After a stint with Hanna-Barbera, he was hired by Ruby-Spears in 1980, first to design characters and backgrounds for its Saturday morning action series “Thundarr the Barbarian,” then to draw presentation boards for new projects.

“Many times, he didn’t have enough to do, or there weren’t enough assignments,” Mr. Spears said. “He was such a prolific guy that he would, on his own, just start sketching out some thoughts.”

Among the far-flung, unrealized projects that Mr. Kirby helped create or contributed to were “Roxie’s Raiders,” an Indiana Jones-style serial about a female adventurer and her allies; “Golden Shield,” about an ancient Mayan hero seeking to save earth in the apocalyptic year 2012; and “The Gargoids,” about scientists who gain superpowers after being infected by an alien virus.

Though none of these series made it past the planning stages, Mr. Kirby was glad to have gainful employment, health insurance for himself and his family and a job where he felt he was respected.

“He’d walk in, and all the young animators would fuss over him and salute him,” said Mark Evanier, the author of “Kirby: King of Comics” and a television writer who has worked for Ruby-Spears and the Kroffts. “It was fun for him to go in there, whereas in the past, when he’d gone to a comic-book company’s offices, it was a contentious atmosphere and a lot of emotional baggage.”

In an e-mail message, Lisa Kirby, one of Mr. Kirby’s daughters, wrote, “My dad always spoke well of Ruby-Spears, and that they treated him fairly.”

For more than two decades, the work that Mr. Kirby created for Ruby-Spears — an estimated 600 production boards — remained boxed up and unseen while the studio was unsure what to do with it.

“I’m going, ‘Joe, why don’t we just take this stuff and give it away?’ ” Mr. Spears said. But Mr. Ruby, he said, was “absolutely insistent” that “someday, someplace, somebody’s going to want this stuff.”

Last fall Mr. Ruby and Mr. Spears brought the properties to the Kroffts, who have begun adapting their vintage television shows into feature films, and who also saw potential in the Kirby material.

“This is a 20-year business for somebody,” Marty Krofft said.

Unlike the work that Mr. Kirby did for Marvel Comics — whose ownership may be decided by a lawsuit filed last month against Marvel and Disney by the artists’ heirs, who seek the copyrights to many of his lucrative Marvel characters — the control of his animation art is more clear-cut.

During his time with Ruby-Spears, Mr. Kirby was employed under a work-for-hire agreement, which means that his work is the property of the studio, lawyers for the partnership said. Marc Toberoff, a copyright lawyer representing the Kirbys in their suit against Marvel and Disney, said that he reviewed Mr. Kirby’s agreement with Ruby-Spears and that he believed any art produced under it was work for hire.

This affords Ruby-Spears and the Kroffts a wide berth to turn their Kirby properties into movies, television shows, comics, videos games and more — all of which they intend to pursue.

They will face steep competition in a marketplace already saturated with established (and not-so-established) comics characters that major media companies have spent years snapping up for their own development purposes. Compared with decades-old franchises like Batman, Superman and Captain America (the last of which Mr. Kirby created with Joe Simon), unknown properties like Roxie’s Raiders and Golden Shield have only Mr. Kirby’s pedigree to distinguish them.

For Mr. Emanuel, that is more than enough to get behind this cache of rediscovered material.

“You can’t go wrong,” he said. “Just close your eyes and throw a dart. And I only saw 5 percent of it.”